1. Field of the Invention
The invention relates to a processing/observation head for a laser processing device, comprising:
means for focusing a light beam on a focus spot via a first optical path;
means for forming a sharp image of a workpiece to be processed via a second optical path which at least partly coincides with the first optical path, the imaging means comprising laser focusing optics and imaging optics whose optical axes coincide with said second optical path, the focusing means comprising said laser focusing optics and a laser mirror disposed between the laser focusing optics and the imaging optics, which laser mirror makes an angle with the second optical path and at least partly reflects laser light and at least partly transmits visible light.
The invention also relates to a laser processing device comprising such processing/observation head.
Hereinafter, the present invention will be specifically explained for cutting a workpiece, which in the example to be discussed is aluminum foil. However, it will be understood by anyone skilled in the art that with a laser beam other operations can be performed as well, and that other materials can be processed.
2. Description of the Prior Art
Processing a workpiece does not only involve the necessity of providing a suitable tool, in this case a laser beam and associated focusing optics. It is also desired that the operating process can be optically followed. In this respect, it is of course desired that optics are present which provide a sharp image of the processing spot, i.e. the momentary interaction area between laser beam and workpiece. For practical reasons, the focusing optics and the imaging optics should have parts in common. On the other hand, it is desired that the focus of the laser beam can be set without this affecting the focusing of the observation optics.
A processing/observation head of the type mentioned in the opening paragraph is known from U.S. Pat. No. 4,573,467.
In the known processing/observation head, the first and the second optical path only coincide in the focus spot and are further entirely separated from each other. As a result, the laser focusing optics must have relatively large dimensions. Further, the entire head must be moved relative to an object to be processed for obtaining a distance to the workpiece to be processed at which the image is sharp and the light beam is focused on the focus spot.
The present invention provides a laser processing device which meets the above desires and drawbacks and is characterized in that the laser mirror at least partly reflects laser light and at least partly transmits visible light and that the laser focusing optics are displaceable with respect to the laser mirror along the first optical path, and that the imaging optics are displaceable with respect to the laser mirror along the second optical path, such that the mutual distance between the laser focusing optics and the imaging optics, measured along the second optical path, is constant.
The invention also relates to a laser processing device comprising a frame, a manipulator mounted on the frame, such as an XY-table for manipulating a workpiece to be processed, a processing/observation head mounted on the frame above the manipulator.
The invention also relates to a laser processing device comprising a processing/observation head, setting means for displacing, with the supply of control signals and in a direction along said optical axes, the laser focusing optics, the imaging optics, and a support on which, in use, a camera can be mounted and an autofocusing system arranged for generating such control signals which, in use, are supplied to the setting means, that the image formed is sharp.